Increased intracranial pressure is a phenomenon which is considered to be nearly always associated with acute inflammation of the cerebrospinal meninges. This phenomenon is caused by the calling into the rigid bony-walled space within the skull and vertebral column of large amounts of inflammatory exudate, while the absorption is, according to Krehl,1 at the same time probably decreased. This heightened pressure has been regarded generally as one of the most potent factors in causing the symptoms of acute meningitis, and relief has been sought through lowering the pressure by withdrawing the cerebrospinal fluid by means of lumbar puncture.

On account of the intimate relation that has been shown by Cushing2 and others to exist between intracranial and blood-pressures, it was thought that a series of observations on the blood-pressure in cases of epidemic cerebrospinal meningitis would prove of interest, especially when the effect of withdrawal of